Turnkey Cleanroom Solutions And Hvac System Service Provider

VAV Butterfly Valve Control System for Fume Hoods

2025-11-27

Working principle	Working principle
single-channel VAV butterfly valve control system	dual-channel VAV butterfly valve control system
The system consists of a fume hood controller, a face velocity sensor, an analog fast actuator, a butterfly valve, and a power control box. After the fan duct is installed, as the fume hood operates, the air velocity flowing into the fume hood changes with the adjustment of the fume hood window height. The face velocity sensor transmits the measured air velocity information to the fume hood controller with a response time of less than 1 second. The fume hood controller calculates the face velocity using a closed-loop PID controller, referring to the previously set face velocity value (generally set between 0.4-0.6 s/m), and quickly issues a command to the analog fast actuator to rapidly adjust the butterfly valve angle, increasing or decreasing the valve angle to achieve the set face velocity range. The entire response process does not exceed 1 second. Simultaneously, the fast actuator's operating time (0°-90° operating time) must not exceed 2 seconds to quickly operate the valve and promptly return to the set air velocity value, preventing exhaust gas from the fume hood from overflowing into the room.	The system consists of a fume hood controller, face velocity sensor, displacement sensor, analog fast actuator and butterfly valve, and power control box. After the fan and duct are installed, when the fume hood is running, as the height of the fume hood window is adjusted, the displacement sensor first detects the height of the fume hood window and quickly adjusts the angle of the fume hood butterfly valve via a signal. When the position of the fume hood window remains unchanged, the face velocity sensor measures the face velocity of the fume hood and makes precise fine adjustments, further finely adjusting the valve angle to return to the initially set face velocity value.